Heating element for a pasta die and a method for extruding pasta

ABSTRACT

Apparatus for increasing pasta production and for ensuring a more uniform and quality pasta product which includes heating the die face of a die by positioning on the die face an electric resistance heater.

This application is a continuation of application Ser. No. 08/380,996filed Jan. 31, 1995, now abandoned.

FIELD OF THE INVENTION

The present invention relates to a device for heating a die face.

BACKGROUND OF THE INVENTION

Though pasta and its production are attributed to the Chinese hundredsof years ago, the industry can be thought of as being in its infancy.Until recently, in the United States and elsewhere, the industry hasbeen dominated by "Mom and Pop"-type facilities using age-old methodsand recipes handed down over generations through families.

The industry today has evolved to the extent that multinationalcorporations are producing the majority of the pasta consumed in NorthAmerica and most probably in Europe. These multinational companies withfunds for conducting research are now more fully recognizing thechemistry and the dynamics of pasta production on a large or a massscale.

Such production involves using extruders having screws for conveyinglarge quantities of alimentary paste to die faces that are up to andgreater than ten feet long for shaping the paste. The die faces areexpensive to manufacture and are composed primarily of brass alloyshaving a plurality of uniformly shaped machined or molded orifices forproducing pasta such as lasagna, spaghetti, linguine, vermicelli, ziti,fusilli, fettuccine, radiatore, rigatoni, etc.

One of the recognized problems of pasta production is the unevenextrusion of the pasta. Currently, in order to successfully extrude thealimentary paste through a die, the paste is conveyed by the screw to aheader that distributes the paste to a plurality of branched-ports orbarrels located behind the die face and in front of the screw. Some ofthe molded orifices of the die are positioned immediately in front ofthe ports, other orifices are positioned to the right or left of theport. During extrusion it is observed that alimentary paste extrudedover the length of the die face does not extrude evenly. In fact,alimentary paste extruded from die faces located immediately in front ofthe ports extrudes faster than the paste further away from the ports.

As shown in FIG. 1, the result of this uneven extrusion defines aperiodic wave at the lead end of the extrusion. Greater lengths of paste10 are extruded from die orifices (primary orifices) immediately infront of conveying branch ports. Paste extruded through such primaryorifices extrudes at a greater rate than paste extruded from orificesadjacent to such primary orifices (secondary orifices), and at greaterrates than being extruded through tertiary orifices even further removedfrom conveying branch ports. The result is that the lead ends of theextruded paste will develop a tapered profile of ever shorter extrudedlengths of paste 12 until the paste extruded from a second series oforifices is influenced by a second branch port. The uneven extrusionresults in sinewave defined by the broken line 14. The uneven lengthsare undesired as consumers favor a uniform product and because it isalways easier to dry and further process paste of uniform length.

Because the uneven lengths are not desired it is necessary to sever theuneven length and return the extruded paste to a hopper above the screw.Reusing such alimentary paste saves money but creates a less thanperfect food product. A better quality product is prepared by notrecycling the excess or cut-off lengths of paste. Eliminating such astep also reduces production costs.

The present invention recognizes that longer length paste 10 is beingextruded faster than the shorter length paste 12 because extruded pastenearest a branch port is warmer than paste removed in distance from sucha port.

The inventor hypothesized that uniformly heating the die face wouldimprove uniformity of paste extrusion, thus overcoming the problemsidentified above.

It is known to heat dies by embedding heaters in the die body, asdisclosed in U.S. Pat. Nos. 5,192,543 and 5,089,284 herein incorporatedby reference. Such devices also include die orifices which are bothcoated and uncoated, delaying and facilitating heat transfer to thealimentary paste. It is also known to externally heat various surfacesother than the die face itself--see U.S. Pat. No. 4,871,493. Althoughthese devices work satisfactorily, they are quite expensive to fabricateand maintain. For instance, the device disclosed in U.S. Pat. Nos.5,192,543 and 5,089,284 requires machining holes in the die forreceiving electrical resistance heaters. The present invention overcomesthese limitations.

SUMMARY OF THE INVENTION

The present invention in its broadest aspects relates to maintaining themass of a die face at a uniform temperature over its entire length orsurface area to ensure that lengths of alimentary paste are extruded inuniform lengths. The invention also relates to apparatus in associationwith the die mass. In the preferred embodiment of the invention, the dieface is uniformly heated by a heating plate in heat exchange relationwith the die mass to create uniform paste lengths. The present inventionalso relates to heating paste after it has assumed a specific shape andthe shape remains fairly constant. In this manner the paste becomes morefluid and increases extrusion rates.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a prior art illustration of extruded alimentary paste havingthe shape of lasagna. The paste is not extruded uniformly.

FIG. 2 is a side sectional view of a die showing, in phantom andotherwise, lands having progressively smaller cross-sections in thedirection of extrusion.

FIG. 3 is a front view of an elongated die face having a multitude ofextruding orifices.

FIG. 4 is a rear plan view, taken on line 4--4 of FIG. 5 looking in thedirection of the arrows shown, of the die heating plate of theinvention. As shown, the die heating plate of the invention has orificesof similar shape to the orifices of the die face of FIG. 3, but are ofgreater dimension.

FIG. 5 is an end side view of the die face and the die heating plate ofthe invention in heat exchange relation. This view also shows a devicewith lands having a uniform cross section.

FIG. 6 is a front view of a random section of the die heating platemounted on a face of a die.

DETAILED DESCRIPTION OF THE INVENTION

Pasta is prepared by shaping an "alimentary paste" or dough which is aglutinous flour and water mixture. Alimentary pastes or doughs aregenerally made from coarse, hard flours obtained from hard wheat such asthe middlings of durum wheat, often referred to as "semolina flour" or"semolina". In addition, fine flours such as durum flour, wherein 98weight percent passes through a 70 mesh sieve, are also suitable and areintended to fall within the scope of the term "glutinous flour". Theonly requirement for the flour is that it provide a self supportingpaste.

A typical alimentary paste used to prepare pastas suitable for thepresent invention comprises, based on the weight of uncooked pasta,between about 67.0% and 80.0% by weight (solids basis) of semolina flour(having an inherent moisture content of between about 10% and 15% andpreferably between about 11% and about 14% by weight, and a proteincontent of between about 11% and about 14% by weight), the balance beingoptional additives and added water.

More specifically, a suitable paste may be prepared from 10 kg fancydurum patent flour and about 2200 grams of added water; a lower moistureformulation may be prepared by adding about 1500 grams of added water tothe same amount of flour.

The paste may contain additives including release agents such asglycerol monostearate, a sulfhydryl reducing agent and added vitamins,e.g. B-vitamins and eggs.

Water can be introduced in the form of ice before or during extrusion,to prevent swelling of the paste during extrusion. The water, ormoisture, content is preferably between about 20.0% and about 30.0% byweight of the paste. In this application, water or moisture contentrefers to total moisture, that is, inherent moisture, or moisturenaturally present in the flour and other ingredients, as well as addedwater. The term "water" as used herein includes water in all physicalstates, i.e., steam, ice or liquid water, or mixtures thereof.

The flour, water and any additives used may be mixed in any wayconventional in the art, such as by mixing in a vertical cutter mixer(e.g. a Hobart Cutter/Planetary Mixer) for approximately one minute, atwhich time the pasta dough is ready for extrusion in any of theconventional pasta shapes. Alternatively, the components of the pastemay be separately introduced into an extruder without prior mixing.After extrusion the created pasta shapes are then preferably subjectedto a drying step.

Shaped pasta is prepared from the paste by extrusion. Extrusion can beperformed with any acceptable extruder whose die face is modified inaccordance with the invention. The alimentary paste is fed into theextruder wherein it may, optionally, be blended, in the case of ascrew-type extruder, or further blended, if the feedstock was premixedbefore being fed into the extruder, and then forced by internal pressurethrough the channels or lands of a die face having a plurality oforifices forcing the paste to conform to a desired shape. The orificesof the die face are defined by the openings of through lands or channelsin the die head. The cross sections of the lands may decrease, e.g. instepwise fashion, in the direction of extrusion as shown in FIG. 2 ormay have a uniform cross-section as shown in FIG. 5. The shapes of theorifices on the die face determine the profile of the extruded pastashape. Such shapes include spaghetti, fettucine, linguine, rotini,elbows, spirals, shells, ziti, vermicelli, fusilli, tortellini, ravioli,manicotti, lasagna, rote, tortiglioni, or the like. The die face shownin FIG. 3 is used to prepare lasagna.

The alimentary paste passes through the die due to internal pressuregenerated by a rotating screw or screws. Suitable screw speeds rangefrom about 3.5 to 35 revolutions per minute (rpm), and preferably about20 rpm to 23 rpm. A particularly optimal screw speed is about 25 rpm. Ingeneral, screw speeds in excess of about 30 rpm appear to result in acompromised texture and increased starch loss in the pasta product,whereas screw speeds of less than about 3.5 rpm render the extrusionprocess economically unfeasible.

The screw speed is chosen to result in an extrusion rate, for example,in the range of about 50 grams per minute (g/min) (6.6 lb/hr) to about500 g/min (66 lb/hr) or greater, preferably about 175 g/min (23 lb/hr),based on a six-orifice die having approximately two inch deep or longlands.

Optimized extrusion rate appears to be correlated to, inter alia, dietemperature, barrel temperature, port temperature and screw speed. Forexample, at a screw speed of 3.5 rpm and at barrel and port temperaturesof 110° F. and 120° F., respectively, acceptable extrusion rates on asix-orifice die of 62 and 55 g/min result. Whereas, at 110° F. and 10.5rpm, an acceptable extrusion rate of 175 g/min occurs.

Vacuum pressure may or may not be used. If used, a vacuum of about 40 cmHg to about 60 cm Hg preferably about 40 cm Hg may be used.

As shown in FIG. 3 and FIG. 5, the commercial extrusion dies in thealimentary paste art are elongated structures and quite massive, andexpensive to produce. The die 20 and its face 22 are fabricated frombrass. The die face of FIG. 3 is about 37 inches long; it has a width ofabout 4 inches. The die has a thickness of about 11/2 inches, and a massof about fifty pounds. Die face 22 has a plurality of extrusion lands orchannels 24, the lands may or may not be of a uniform cross section. Asshown in FIG. 2, the lands 24 may have progressively smaller crosssections in the direction of extrusion or, as shown in FIG. 5, the crosssections of the lands may be uniform. The lands terminate or defineorifices 25 (FIGS. 3 and 6) at the front face 22 of the die 20. Theinventor has now found that by maintaining a constant and uniformtemperature over the mass of die face 22 so that pasta is heated at itsextrusion point, i.e., at 25 (on FIG. 3) and not within the lands orchannels of the die, a more uniform product in terms of length andoverall composition is obtained.

The constant temperature over the mass of the die face 22 is maintainedby die heating plate 26 shown positioned on the die face in FIGS. 2, 5and 6.

Die heating plate 26 as shown in FIGS. 2, 3 and 5 has a thickness ofpreferably 3/4 inch, and sides 28 for defining a depth and an open backend 30. The heating plate 26 is preferably constructed of the same metalcomposition as the face of the die and the die to assist in heattransfer. Specifically, if die 20 and its face 22 are constructed frombrass, so too is die heating plate 26. When the compositions of the die,die face and die heating plate cannot be duplicated, the heating plateshould have thermo-conductivity and expansion properties equal to orvery similar to the die face and die.

The face of heating plate 26 includes machined openings 32. Thearrangement and the number of openings in the die heating platecorrespond in arrangement or position, shape and number to orifices 25of the die face. Although openings 32 are similar in shape to orifices25, they are larger, allowing extruded alimentary paste to passtherethrough without encountering the surfaces defining openings 32.

Positioned within the open back end 30 of heating die plate 26 is anelectrical resistance heating coil 34. In the embodiment shown, coil 34is composed of a nicke-chromium alloy and it is fourteen gauge. The sizeof the wire is not critical but it must be able to generate sufficientheat to uniformly heat the mass of the die face. Heating coil 34, asshown in FIG. 4, is positioned in a serpentine manner about openings 32within the back of the die heating plate so as not to block the openings32. This arrangement allows extruded paste to pass from orifices 25through openings 32 without interference. It is noted as seen in FIGS.2, 4 and 5 that the rear face 30 of the heated plate 28 has channelmeans 40 formed therein within which the electrical resistance heatingcoil 34 is disposed. Serpentine positioning is not critical, but it isdesirable to arrange heating coil 34 in this way so that it occupiessignificant area allowing for maximum distribution of heat withoutblocking openings 32. Any arrangement that accomplishes this result isdesired. For example, a core heater or the like can be used.

Electrical resistance coil 34 has two leads 35 and 37 which may passthrough heating die plate 26 as shown. These leads are connected to anelectrical power supply (not shown).

It is, of course, necessary to electrically insulate the heating coil 34from the die heating plate as it passes through the die heating plate toprevent losses in resistance. Insulating structure for this purposeincludes mica tape with a polytetrafluoroethylene-treated overbraidknown in the art.

In addition, it is necessary to separate heating coil 34 from the dieface and die heating plate. Failure to insulate the coil from othermetal parts will result in a drastic drop in resistance and a reductionin the heating capacity of the coil. Therefore, the coil is embedded ina non-electric conductive heat transfer material such as a furnaceretort composition or a cement composition resistant to thermal shock.The composition, however, must be pottable and have excellent mechanicalbonding characteristics. In addition it must be easily removable when itbecomes necessary to either replace the coil or clean the apparatus forsanitary or health reasons. A product satisfying the above criteria issold by Omega Engineering, Inc., of Stamford, Conn., under the trademarkOMEGABOND 600 or OB-600.

Essentially OB-600 is a powder and it is mixed with water to create acomposition having a consistency such that it can be troweled onto thecoil and layered so as to electrically insulate the coil.

When the heat transfer non-electrically conductive cement is dry or setthe die heating plate is mounted to the face of the die as shown in FIG.5. Specifically, the back end 30 of the die heating plate as shown inFIGS. 2 and 5 is mounted to die face 22. When the die heating plate 26is positioned on die face 22, openings 32 are superposed over orifices25. Because openings 32 are larger in dimension than orifices 25,orifices 25 are readily viewed by looking through opening 32 as shown inFIG. 6.

Supplying a current to the resistance heating wire heats the die heatingplate to above the normal operating temperature of the die; the heatingplate 26 will, by radiation and conduction, uniformly increase thetemperature of the mass of the die face and the lands of the die. Thisheating of the die face and die raises the temperature of the extrudedpaste facilitating extrusion of the alimentary paste.

In a pilot study using the die described above, a single orifice diehaving two-inch deep lands of uniform cross section was connected toMapimipianti GF20 extruder.

Extruder conditions and die heating plate conditions were maintained asset forth in Table 1 below.

                                      TABLE I                                     __________________________________________________________________________    HEATED DIE RUNS GBRC - AUGUST 2, 3, 4, 1994                                      Current                                                                            Force                                                                              Dough          Exit         %        Heating                        (Amps on                                                                           (Volts on                                                                          Temp into                                                                           Pressure                                                                           Motor                                                                             Dough                                                                             Barrel                                                                             Rate                                                                              Cooking                                                                           Hedonic                                                                            Die Plate                   Run                                                                              Heater)                                                                            Heater)                                                                            Die   (bars)                                                                             Amps                                                                              Temp                                                                              Temp (lb/hr)                                                                           Loss                                                                              (1-5)*                                                                             Temp.                       __________________________________________________________________________    1  0    0    120° F.                                                                      148  5   124° F.                                                                    120° F.                                                                     27.5                                                                              8.9 3.5  Control                     2  6    16   126° F.                                                                      132  4-5 147° F.                                                                    120° F.                                                                     33.2                                                                              9.7 4.0  160° F.              3  12   27   127° F.                                                                      130  4-5 172° F.                                                                    120° F.                                                                     34.5                                                                              12.8                                                                              1.5  206° F.              4  0    0     96° F.                                                                      208  5-6 108° F.                                                                     83° F.                                                                     24.1                                                                              8.9 2.7  Control                     5  3    7    102° F.                                                                      198  5-6 116° F.                                                                     83° F.                                                                     26.5                                                                              8.5 2.8  130° F.              6  6    15   105° F.                                                                      192  5-6 127° F.                                                                     83° F.                                                                     29.1                                                                              8.7 3.3  160° F.              7  0    0    120° F.                                                                      175  7   137° F.                                                                    120° F.                                                                     29.8                                                                              9.3 2.0  Control                     8  3    8    124° F.                                                                      173  7   143° F.                                                                    120° F.                                                                     32.3                                                                              9.9 2.5  160° F.              9  6    15   126° F.                                                                      170  7   154° F.                                                                    120° F.                                                                     35.4                                                                              10.4                                                                              3.0  200° F.              __________________________________________________________________________     Samples #1-6 were run at 30.0% calculated dough moisture.                     Samples #7-9 were run at 27.5% calculated dough moisture.                     Samples #4-9 were run using a die insert with reduced flow restriction.       *For 1-5 hedonic rating 1 = poor 5 = excellent.                          

In greater detail run numbers 1, 4 and 7 are control runs. In thesethree instances, no electrical energy, or other energy source is used toraise the temperature of the die heating plate. In other words the dieheating runs 1, 4 and 7 were not influenced by the heating plate.

Pasta dough samples 1-3 had a moisture content of 30.0% and the dieheating plate was heated in runs 2 and 3. As shown, increased dieheating plate temperatures caused a reduction in the pressure asextruded dough was made more fluid by the increase in dough temperatureattributed to the heating die plate. A reduction in the currentrequirement of the extruder is also exhibited. As shown, pastaproduction increased for runs 2 and 3 relative to run number 1. Finally,for at least run number 2, a very acceptable hedonic ratio of 4.0 wasachieved for the extended pasta.

Although run number 3 showed improved pasta production rates over runs 1and 2, pasta quality in run number 3 was poorer relative to control (runnumber 1) and run number 2. This indicates that there may be one or moreparameters (dough temperature, heating plate temperature, screw speed,etc. ) in addition to heating the die heating plate that must beoptimized to obtain overall improved quality pasta during increasedproduction.

Table I also shows that by using the heating plate of the claimedinvention pasta production is increased and pasta quality is improved inrun numbers 5 and 6 relative to control run number 4.

Runs 7-9 were conducted using pasta having a moisture content of 27.5%.Reduced moisture content increases current demands of the extruded pastarelative to runs 1-6, but has advantages in that pasta sent to the dryercontains less moisture and, therefore, dries faster. Again, as shown,using the heating die plate of the invention pasta is produced atgreater rates and it is of improved quality.

Table II shows results of commercial production using the heating dieplate 26 of FIG. 3. The heating 26 plate was attached by screwing thedie heating plate 26 to the face 22 of the die 20. The orifices of theheating plate 32 are of dimensions allowing for extrusion of lasagna,without the extruded paste touching the walls defining the openings 32of the die heating plate 26. A control test included the die heatingplate 26 attached to the die face 22, but it was not heated by anoutside or independent heating source.

                                      TABLE II                                    __________________________________________________________________________                                 %     %     %       %                                  MOTOR PRODUCT                                                                             %     RATE DOUGH CHANGE                                                                              CHANGE  COOKING                      TESTS AMPS  TEMP. RECYCLE                                                                             per/hr.                                                                            MOISTURE                                                                            IN RATE                                                                             IN RECYCLE                                                                            LOSS                         __________________________________________________________________________    CONTROL                                                                             53.1  115° F.                                                                      21%   917  32.5% 0     0       5.49%                        TEST 1                                                                              53.7  115° F.                                                                      17.5% 993  32.4% 7.7%  -16.7%                               TEST 2                                                                              55.8  117° F.                                                                      14%   1050 31.9% 12.7% -33.3%  6.06%                        TEST 3                                                                              56.2  120° F.                                                                      18%   1000 31.6% 8.3%  -14.3%  6.69%                        TEST 4                                                                              50.8  116° F.                                                                      20%   1063 32.8% 13.7% -4.8%   6.24%                        __________________________________________________________________________

Tests numbered 1-4 were conducted by varying the current supplied to theheating die plate. As shown the heating plate improved production,reduced pasta recycle and produced a better quality pasta relative tothe control sample. Of course, the control test was conducted withoutactivating or supplying current to the heating die plate.

Table III below is a report of the thickness (top and bottom) of alength of lasagna. The result for the control is not reported. As shown,the thicknesses obtained for Test Samples 1-4 are within acceptabletolerances of the industry.

                  TABLE III                                                       ______________________________________                                        HEATED DIE RUNS                                                               AVERAGE LASAGNA THICKNESS AND                                                 LENGTH ON STICKS                                                                             TEST 1                                                                              TEST 2  TEST 3  TEST 4                                   ______________________________________                                        AVERAGE LASAGNA  50.6    48.4    47.4  46.3                                   THICKNESS TOP (0.001")                                                        AVERAGE LASAGNA  52.8    54.0    53.8  52.7                                   THICKNESS BOTTOM (0.001")                                                     AVERAGE LASAGNA  51.7    51.2    50.6  49.5                                   THICKNESS TOTAL (0.001")                                                      AVERAGE LASAGNA  2.2     5.6     6.4   6.4                                    THICKNESS DIFFERENCE                                                          (0.001")                                                                      AVERAGE LASAGNA LENGTH                                                                         20.7    20.6    20.8  20.5                                   (1")                                                                          ______________________________________                                    

It has also been observed that in using the heating plate of theinvention, as described, the phenomena known as checking is lessened,ameliorated or eliminated during pasta storage. Checking refers toproduct crumbling or disintegration during storage when pasta looses orgains moisture. The phenomena is exacerbated by poor extrusion, dryingor storage conditions and the phenomena is observed, most frequently, inpastas at the beginning and end of an extrusion process. It is at thistime that temperature and humidity changes in the drying chamberfluctuate considerably and are least uniform. "Checking" observationswere made on pasta samples produced conventionally, i.e., without theheating plate (samples A-H) and on samples produced with the aid of anactivated heating die plate (samples I-J). After thirteen weeks, at 100°F., under dry conditions (approximately 0% humidity) all samples weresubjected to 90° F. at 75% R.H. for four days and then held at roomconditions for three days. Obviously, these extreme conditions weredesigned to test for checking based on a worst-case scenario. See TableIV.

                  TABLE IV                                                        ______________________________________                                        LENGTH OF TIME STORED - WEEKS                                                 A = Accept; F - Failed; UT = Under Test                                                             Storage Temps                                                                 100/Dry                                                 ______________________________________                                        A   New Hope Spaghetti, Variable 101                                                                      F-13*1                                                Low Temperature Dryer, 100% Semolina                                      B   New Hope Spaghetti, Variable 110                                                                      F-13*1                                                Low Temperature Dryer, 100% Regrind                                       C   New Hope Spaghetti, Variable 111                                                                      F-13*1                                                Low Temperature Dryer 100% Flour                                          D   New Hope Spaghetti, Variable 321                                                                      F-13*1                                                High Temperature Dryer, 100% Regrind                                      E   New Hope Spaghetti, Variable 330                                                                      F-13*1                                                High Temperature Dryer, 100% Regrind                                      F   New Hope Spaghetti, Variable 331                                                                      F-13*1                                                High Temperature Dryer, 100% Flour                                        G   Crescendo Spaghetti     F-13*1                                            H   Buffalo Lasagna, Control                                                                              F-13*1                                            I   Buffalo Lasagna, Test 1 F-13*1                                            J   Buffalo Lasagna, Test 2 A-13*2                                            ______________________________________                                         *1 After 13 weeks at 100°, dry samples were transferred to             90° F./75% RH for 4 days, then held at RT for 3 days. All products     failed due to checking; however, the checking was not as evident on J         sample as on samples A-I.                                                     *2 Borderline checking observed.                                         

All of the pasta experienced checking; however, checking in sample J wasnot as evident as it was on samples A-I. Sample J is evidence thatchecking is significantly improved using the device of the claimedinvention. The die heating plate of the invention, positioned on or infront of a die face appears to create storage stability. It isspeculated that sample I did not exhibit improved checking becauseextreme storage conditions were employed. It is speculated that Sample Iwould exhibit improved checking results, relative to samples A-H, if itwere exposed to less extreme conditions.

It is noted that other heating devices may be substituted for theheating coils of the die heating plate. Such devices may include aheated water jacket or heated pipes in contact with the die heatingplate or by directing hot air over the die heating plate. It is alsocontemplated that auxiliary or additional heaters may be used inassociation with other parts of the die for heating the die or portionsof the die defining lands or orifices of the die.

In summary the die heating plate of the invention saves on the wear andtear of expensive extruding equipment, it eliminates the unevenextrusion rate of extruding alimentary paste, it improves checkingqualities, it is easy to fabricate and install, and allows for the easyretrofit of existing pasta extruders. It also produces savings in powerrequirements.

Having described the subject matter of the present invention, it shouldbe apparent that many substitutions, modifications and variations of theinvention are possible in light of the above teachings. It is thereforeto be understood that the invention as taught and described herein isonly limited by the appended claims.

What is claimed is:
 1. An apparatus for extruding uniform alimentarypasta lengths comprising a die having a front die face, said die havinga plurality of lands formed therethrough and terminating in a pluralityof orifices at said front die face, means for extruding alimentary pastethrough said lands and out of said orifices for producing shaped lengthsof alimentary pasta, a heated plate having a front face and an oppositerear face, said heated plate being mounted on said die with its rearface disposed in abutting facing relationship to said front die face,said heated plate having a plurality of openings formed therethroughsuperposed over said orifices and being similar in number and shape tosaid orifices but larger in dimension, and heating means disposedadjacent the rear face of said heated plate and occupying significantarea of the rear face of said heated plate to uniformly heat the entirefront face of said die to ensure uniform flow of alimentary pastethrough said orifices.
 2. Apparatus as defined in claim 1 wherein therear face of said heated plate has channel means formed therein, saidheating means comprising an electrical resistance heating coil disposedwithin said channel and being embedded within a dielectric heatconductive material.
 3. Apparatus as defined in claim 2 wherein saidcoil is positioned in serpentine manner about the openings in saidheated plate to further ensure that the adjacent front face of the dieis uniformly heated.
 4. Apparatus as defined in claim 2 wherein saidcoil is formed of a nickel-chromium alloy.
 5. Apparatus as defined inclaim 1 wherein said lands have progressively smaller cross-sections inthe the direction of extrusion.
 6. Apparatus as defined in claim 1including additional heating means within the die for heating the die toensure that portions of the die defining the orifices of the die areheated to a uniform temperature.
 7. Apparatus as defined in claim 1wherein said die and said heated plate have substantially the samethermo-conductivity and expansion properties.